A heat pump system is a common adjusting system for an air conditioner presently, and generally includes an outdoor heat-exchanging system, a heat pump unit and an indoor air conditioner terminal system, three of which are connected via corresponding pipelines. The heat pump unit drives refrigerant to flow in the pipelines; in the outdoor heat-exchanging system, the refrigerant exchanges heat with exterior matters (such as water or air) to absorb heat from the exterior matters or discharge heat; and in the indoor air conditioner terminal system, the refrigerant exchanges heat with indoor air to discharge heat into the room or absorb heat from the indoor air, thereby adjusting an indoor temperature.
In order to ensure the performance of the refrigerant, a purifying device is generally arranged in the pipelines for absorbing and filtering moisture, residual acid or other impurities in the refrigerant, and retaining the impurities in the purifying device, thereby purifying the refrigerant. For adapting to the bidirectional flowing of the refrigerant in the heat pump system and meanwhile simplifying the structure of the purifying device, a bidirectional filter is generally provided in the purifying device for purifying the refrigerant.
Reference is made to FIGS. 1 and 2, wherein FIG. 1 is a schematic view showing the structure of a bidirectional filter in the prior art; FIG. 2 is an exploded view of a control valve component in the bidirectional filter of FIG. 1; and FIG. 2-1 and FIG. 2-2 are schematic views showing the operating principle of the control valve component in two states respectively, FIG. 2-1 is a schematic view showing the operating principle of the control valve component with an outlet being closed and an inlet being opened, and FIG. 2-2 is a schematic view showing the operating principle of the control valve component with the outlet being opened and the inlet being closed.
The bidirectional filter in the prior art includes a housing 200 of a substantially cylindrical structure, and an inner chamber is formed inside the housing 200. The housing 200 further includes two connecting pipes 201 and 202 located at two ends of the cylindrical structure, respectively. The connecting pipes 201 and 202 each have an inner end communicated to the inner chamber and an outer end connected to a corresponding pipeline. Two control valve components 400 are respectively arranged at locations close to two ends of the inner chamber and divide the inner chamber into a filter chamber 211 located at the middle and transitional chambers 212 and 213 respectively located at the two ends, and a filter core 300 is arranged in the filter chamber 211.
As shown in FIG. 2, the control valve component 400 includes a frame body 440, an outlet blocking piece 430 and an inlet blocking piece 450. The frame body 440 is of a disc shape, and a periphery thereof is hermetically connected to an inner wall of the housing 200, and the frame body 440 is provided with an outlet 441 and an inlet 442. The outlet blocking piece 430 is located at an outer side of the frame body 440 and is capable of cooperating with the outlet 441 under the action of an elastic member 420. The inlet blocking piece 450 is located at an inner side of the frame body 440 and is capable of cooperating with the inlet 442 under the action of an elastic member 460. As shown in the Figures, the outlet 441 is located at the middle of the frame body 440, and the inlet 442 is located around the outlet 441. The outlet blocking piece 430 is fixed by a rivet 410 and is slidable in an extending direction of the rivet 410. Two ends of the elastic member 420 are respectively supported on the rivet 410 and an outer side surface of the outlet blocking piece 430. The elastic member 460 is a spring leaf, the inlet blocking piece 450 is mounted at one end of the spring leaf, and in a free state, the inlet blocking piece 450 hermetically cooperates with the inlet 442 under the action of the spring leaf.
Referring to FIGS. 1, 2-1 and 2-2, the operating process of the bidirectional filter is described as follow. Under the action of the heat pump unit, the refrigerant flows in the pipelines at an appropriate pressure. The control valve component 400 at the left side (in reference with FIG. 1) is at the state shown in FIG. 2-1 when the refrigerant flows into the bidirectional filter from the connecting pipe 202 and flows out of the connecting pipe 201, and the inlet blocking piece 450 is moved inwards under the pressure of the refrigerant to be separated from the inlet 442, thus the inlet 442 is opened. At the same time, the outlet blocking piece 430 is remained in hermetical cooperation with the outlet 441 under the pressure of the refrigerant. At this time, the refrigerant flows from the transitional chamber 212 into the filter chamber 211 through the inlet 442, and then flows to the middle of the filter core 300 through the periphery of the filter core 300 and then flows to an inner side of the outlet 441 of the control valve component 400 at the right side. At this time, the control valve component 400 at the right side is at the state shown in FIG. 2-2, the outlet blocking piece 430 is moved outwards under the pressure of the refrigerant to be separated from the outlet 441, thus the outlet 441 is opened; and the inlet blocking piece 450 is remained in hermetical cooperation with the inlet 442 under the pressure of the refrigerant. At this time, the refrigerant flows out of the filter chamber 211 through the outlet 411 of the control valve component 400 at the right side, and flows out of the bidirectional filter through the transitional chamber 213 at the right side and the connecting pipe 201.
When the refrigerant flows into the bidirectional filter from the connecting pipe 201 and flows out through the connecting pipe 202, the states of the control valve component 400 at the left side and the control valve component 400 at the right side are switched, that is, the refrigerant flows through the inlet 442 of the control valve component 400 at the right side, the filter core 300, and the outlet 441 of the control valve component 400 at the left side in sequence. Through the above process, the bidirectional filter may purify the refrigerant when the refrigerant flows in different directions.
During the practical application, the operating process is complicated, thus the pressure of the refrigerant in the pipeline is generally variable. When the refrigerant has a relatively high pressure, the outlet blocking piece 430 is moved by a relatively great distance, which may reduce a flowing section between an outer side surface of the outlet blocking piece 430 and an inner end port of the connecting pipe 201 or the connecting pipe 202, cause a greater resistance to flow of the refrigerant, and cause a throttling phenomenon at an inner end of the connecting pipe 201 or the connecting pipe 202, and in a worse case, may cause a sharp decrease of the temperature at this part and cause frosting. When the outlet blocking piece 430 is moved by a great distance under the pressure of the refrigerant, the connecting pipe 201 or the connecting pipe 202 may be blocked, which may in turn cause a failure of the bidirectional filter. Therefore, a problem to be solved by those skilled in the art is to reduce the disadvantageous impacts on the bidirectional filter caused by the pressure variation of the refrigerant.
Furthermore, an abrupt change or instability of the pressure of the refrigerant may cause deformation of the outlet blocking piece 430, which may in turn affect the cooperation relationship between the outlet blocking piece 430 and the outlet 441, thus the outlet 441 can not be sealed. In this way, a part of the refrigerant may directly flow into the filter chamber through the outlet 441 of the control valve component 400 at one side, and flow out through the outlet of the control valve component 400 at the other side, which causes a partial failure of the bidirectional filter.